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+/*
+ * -------------------------------------------------------------
+ *
+ * Module: semaphore_timedwait.c
+ *
+ * Purpose:
+ * Semaphores aren't actually part of the PThreads standard.
+ * They are defined by the POSIX Standard:
+ *
+ * POSIX 1003.1b-1993 (POSIX.1b)
+ *
+ * -------------------------------------------------------------
+ *
+ * --------------------------------------------------------------------------
+ *
+ * Pthreads-win32 - POSIX Threads Library for Win32
+ * Copyright(C) 1998 John E. Bossom
+ * Copyright(C) 1999,2002 Pthreads-win32 contributors
+ *
+ * Contact Email: rpj@ise.canberra.edu.au
+ *
+ * The current list of contributors is contained
+ * in the file CONTRIBUTORS included with the source
+ * code distribution. The list can also be seen at the
+ * following World Wide Web location:
+ * http://sources.redhat.com/pthreads-win32/contributors.html
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library in the file COPYING.LIB;
+ * if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
+ */
+
+#ifndef _UWIN
+#include <process.h>
+#endif
+#ifndef NEED_FTIME
+#include <sys/timeb.h>
+#endif
+
+#include "pthread.h"
+#include "semaphore.h"
+#include "implement.h"
+
+
+int
+sem_timedwait (sem_t * sem, const struct timespec * abstime)
+ /*
+ * ------------------------------------------------------
+ * DOCPUBLIC
+ * This function waits on a semaphore possibly until
+ * 'abstime' time.
+ *
+ * PARAMETERS
+ * sem
+ * pointer to an instance of sem_t
+ *
+ * abstime
+ * pointer to an instance of struct timespec
+ *
+ * DESCRIPTION
+ * This function waits on a semaphore. If the
+ * semaphore value is greater than zero, it decreases
+ * its value by one. If the semaphore value is zero, then
+ * the calling thread (or process) is blocked until it can
+ * successfully decrease the value or until interrupted by
+ * a signal.
+ *
+ * If 'abstime' is a NULL pointer then this function will
+ * block until it can successfully decrease the value or
+ * until interrupted by a signal.
+ *
+ * RESULTS
+ * 0 successfully decreased semaphore,
+ * -1 failed, error in errno
+ * ERRNO
+ * EINVAL 'sem' is not a valid semaphore,
+ * ENOSYS semaphores are not supported,
+ * EINTR the function was interrupted by a signal,
+ * EDEADLK a deadlock condition was detected.
+ * ETIMEDOUT abstime elapsed before success.
+ *
+ * ------------------------------------------------------
+ */
+{
+ int result = 0;
+
+#ifdef NEED_FTIME
+
+ struct timespec currSysTime;
+
+#else /* NEED_FTIME */
+
+ struct _timeb currSysTime;
+
+#endif /* NEED_FTIME */
+
+ const DWORD NANOSEC_PER_MILLISEC = 1000000;
+ const DWORD MILLISEC_PER_SEC = 1000;
+ DWORD milliseconds;
+
+ if (sem == NULL)
+ {
+ result = EINVAL;
+ }
+ else
+ {
+ if (abstime == NULL)
+ {
+ milliseconds = INFINITE;
+ }
+ else
+ {
+ /*
+ * Calculate timeout as milliseconds from current system time.
+ */
+
+ /* get current system time */
+
+#ifdef NEED_FTIME
+
+ {
+ FILETIME ft;
+ SYSTEMTIME st;
+
+ GetSystemTime(&st);
+ SystemTimeToFileTime(&st, &ft);
+ /*
+ * GetSystemTimeAsFileTime(&ft); would be faster,
+ * but it does not exist on WinCE
+ */
+
+ filetime_to_timespec(&ft, &currSysTime);
+ }
+
+ /*
+ * subtract current system time from abstime
+ */
+ milliseconds = (abstime->tv_sec - currSysTime.tv_sec) * MILLISEC_PER_SEC;
+ milliseconds += ((abstime->tv_nsec - currSysTime.tv_nsec) + (NANOSEC_PER_MILLISEC/2)) / NANOSEC_PER_MILLISEC;
+
+#else /* NEED_FTIME */
+ _ftime(&currSysTime);
+
+ /*
+ * subtract current system time from abstime
+ */
+ milliseconds = (abstime->tv_sec - currSysTime.time) * MILLISEC_PER_SEC;
+ milliseconds += ((abstime->tv_nsec + (NANOSEC_PER_MILLISEC/2)) / NANOSEC_PER_MILLISEC) -
+ currSysTime.millitm;
+
+#endif /* NEED_FTIME */
+
+
+ if (((int) milliseconds) < 0)
+ milliseconds = 0;
+ }
+
+#ifdef NEED_SEM
+
+ result = (pthreadCancelableTimedWait ((*sem)->event, milliseconds));
+
+#else /* NEED_SEM */
+
+ result = (pthreadCancelableTimedWait ((*sem)->sem, milliseconds));
+
+#endif
+
+ }
+
+ if (result != 0)
+ {
+
+ errno = result;
+ return -1;
+
+ }
+
+#ifdef NEED_SEM
+
+ ptw32_decrease_semaphore(sem);
+
+#endif /* NEED_SEM */
+
+ return 0;
+
+} /* sem_timedwait */